Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 8/9/2009
Publication Date: 8/9/2009
Citation: Paulson, A.L., Bannantine, J.P., Chacon, O., Fenton, R.J., Zinniel, D.K., Mcvey, D.S., Smith, D.R., Czuprynski, C.J., Barletta, R.G. 2009. Mycobacterium avium subsp. paratuberculosis PPE Protein MAP1152 and Conserved Protein MAP1156 are Antigenic in Experimentally and Naturally Infected Cattle [abstract]. Interpretive Summary:
Technical Abstract: Mycobacterium avium subsp. paratuberculosis (MAP) causes Johne’s Disease (JD) in ruminants resulting in significant production losses. An insertion mutation upstream from the MAP1152-MAP1156 region causes a change in colony morphotype and results in an attenuated phenotype in bovine monocyte derived macrophages. The MAP1152-MAP1156 genomic region was analyzed computationally. MAP1152 encodes a PPE protein, while MAP1156 encodes a member of the uncharacterized protein family (UPF0089). Transcriptional analysis suggests that these genes may be organized in two overlapping operons. Maltose-binding protein tagged recombinant proteins were purified from E. coli clones by affinity chromatography. The antigenicity of MAP1152 and MAP1156 was examined against sera of experimentally infected mice and rabbits; and experimentally and naturally infected cattle. Both proteins demonstrated antigenic properties by Western Blot and ELISA analyses. Western blot analysis indicated that MAP1156 yielded a stronger positive signal than MAP1152 against sera from cattle with JD. ELISA was used to quantify the seroreactivity of these recombinant proteins against the IdexxR reference antigen. MAP1152 displayed 2- to 3-fold greater reactivity (optical density values) against positive sera as compared to negative controls (p < 0.001). Likewise, the reactivity of MAP1156 was 2 to 4-fold greater for positive sera (p < 0.05.). In contrast, the Idexx reference antigen reacted 5 to 12-fold greater with positive than negative sera (p < 0.0001). However, for the majority of the samples, tests with either MAP1152 or MAP1156 as capture antigen, yielded the same classification of positive or negative status as the Iddexx antigen. However, MAP1156 was more reactive against negative sera, adding variability to this classification, and creating misclassification of negative sera as positive in 1 sample of 4 tested. The data presented suggest that MAP1152 and MAP1156 are antigenic and hold strong potential as vaccine candidates or differential diagnostic antigens if used in conjunction with the corresponding attenuated mutants.